Motor drives and other electrical systems include a variety of electrical components, such as capacitors, inductors, resistors, etc., often employed in filter circuits. For instance, active front-end rectifiers for motor drives and other power conversion systems often include LC or LCL filters with individual inductive and capacitive components. Performance of these input filters depends at least partially on provision of the designed device impedance value, wherein impedance changes and/or imbalance between corresponding components in multiphase power distribution systems can lead to adverse performance, including loss of efficiency, instability, increased noise, etc. In addition to motor drives and power conversion systems, electrical systems generally operate best when passive electrical component values are at their proper designed impedance values. Accordingly, diagnosing system performance issues often involves assessing the impedance values of various electrical components. Manual impedance measurement is often difficult and time-consuming, and previous in situ impedance measurement techniques suffer from computation complexity preventing or inhibiting real-time automatic device impedance scrutiny while the overall system is operating. Moreover, conventional measurement techniques may be incapable of measuring certain component impedance values under real-life operating conditions, such as inductor impedance during saturation. In addition, it is often desired to obtain impedance values corresponding to different frequencies, and conventional approaches often involve significant manual testing efforts and/or excessive computational overhead for Fourier analysis and the like. Accordingly, a need remains for improved methods and apparatus for determining the impedance of electrical components.